The USB driver uses four USB Request Blocks for RX. Before submitting one, it allocates a 32768 byte skb for the RX data. This allocation can fail, maybe due to temporary memory fragmentation. When the allocation fails, the corresponding URB is never submitted again. After four such allocation failures, all RX stops because the driver is not requesting data from the device anymore. Don't allocate a 32768 byte skb when submitting a USB Request Block (which happens very often). Instead preallocate 8 such skbs, and reuse them over and over. If all 8 are busy, allocate a new one. This is pretty rare. If the allocation fails, use a work to try again later. When there are enough free skbs again, free the excess skbs. Also, use WQ_BH for the RX workqueue. With a normal or high priority workqueue the skbs are processed too slowly when the system is even a little busy, like when opening a new page in a browser, and the driver runs out of free skbs and allocates a lot of new ones. This is more or less what the out-of-tree Realtek drivers do, except they use a tasklet instead of a BH workqueue. Tested with RTL8723DU, RTL8821AU, RTL8812AU, RTL8812BU, RTL8822CU, RTL8811CU. Closes: https://lore.kernel.org/linux-wireless/6e7ecb47-7ea0-433a-a19f-05f88a2edf6b@xxxxxxxxx/ Signed-off-by: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx> --- v2: - Pass the appropriate gfp_t flags as a parameter to rtw_usb_rx_resubmit() instead of using in_interrupt(). Call it "gfp" instead of "priority". - Initialise rx_skb a little earlier in rtw_usb_rx_resubmit(). - Move C2H_ADAPTIVITY in a new patch (2/3). - Allow the driver to allocate 4 more persistent skbs after the initial 8. --- drivers/net/wireless/realtek/rtw88/usb.c | 79 +++++++++++++++++++----- drivers/net/wireless/realtek/rtw88/usb.h | 3 + 2 files changed, 67 insertions(+), 15 deletions(-) diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c index 4dbd5167faa4..b405f8317021 100644 --- a/drivers/net/wireless/realtek/rtw88/usb.c +++ b/drivers/net/wireless/realtek/rtw88/usb.c @@ -585,7 +585,7 @@ static void rtw_usb_rx_handler(struct work_struct *work) goto skip_packet; } - skb = alloc_skb(skb_len, GFP_KERNEL); + skb = alloc_skb(skb_len, GFP_ATOMIC); if (!skb) { rtw_dbg(rtwdev, RTW_DBG_USB, "failed to allocate RX skb of size %u\n", @@ -612,32 +612,70 @@ static void rtw_usb_rx_handler(struct work_struct *work) rx_desc += next_pkt; } while (rx_desc + pkt_desc_sz < rx_skb->data + rx_skb->len); - dev_kfree_skb_any(rx_skb); + if (skb_queue_len(&rtwusb->rx_free_queue) >= RTW_USB_RX_SKB_NUM) + dev_kfree_skb_any(rx_skb); + else + skb_queue_tail(&rtwusb->rx_free_queue, rx_skb); } } static void rtw_usb_read_port_complete(struct urb *urb); -static void rtw_usb_rx_resubmit(struct rtw_usb *rtwusb, struct rx_usb_ctrl_block *rxcb) +static void rtw_usb_rx_resubmit(struct rtw_usb *rtwusb, + struct rx_usb_ctrl_block *rxcb, + gfp_t gfp) { struct rtw_dev *rtwdev = rtwusb->rtwdev; + struct sk_buff *rx_skb; int error; - rxcb->rx_skb = alloc_skb(RTW_USB_MAX_RECVBUF_SZ, GFP_ATOMIC); - if (!rxcb->rx_skb) - return; + rx_skb = skb_dequeue(&rtwusb->rx_free_queue); + if (!rx_skb) + rx_skb = alloc_skb(RTW_USB_MAX_RECVBUF_SZ, gfp); + + if (!rx_skb) + goto try_later; + + skb_reset_tail_pointer(rx_skb); + rx_skb->len = 0; + + rxcb->rx_skb = rx_skb; usb_fill_bulk_urb(rxcb->rx_urb, rtwusb->udev, usb_rcvbulkpipe(rtwusb->udev, rtwusb->pipe_in), rxcb->rx_skb->data, RTW_USB_MAX_RECVBUF_SZ, rtw_usb_read_port_complete, rxcb); - error = usb_submit_urb(rxcb->rx_urb, GFP_ATOMIC); + error = usb_submit_urb(rxcb->rx_urb, gfp); if (error) { - kfree_skb(rxcb->rx_skb); + skb_queue_tail(&rtwusb->rx_free_queue, rxcb->rx_skb); + if (error != -ENODEV) rtw_err(rtwdev, "Err sending rx data urb %d\n", error); + + if (error == -ENOMEM) + goto try_later; + } + + return; + +try_later: + rxcb->rx_skb = NULL; + queue_work(rtwusb->rxwq, &rtwusb->rx_urb_work); +} + +static void rtw_usb_rx_resubmit_work(struct work_struct *work) +{ + struct rtw_usb *rtwusb = container_of(work, struct rtw_usb, rx_urb_work); + struct rx_usb_ctrl_block *rxcb; + int i; + + for (i = 0; i < RTW_USB_RXCB_NUM; i++) { + rxcb = &rtwusb->rx_cb[i]; + + if (!rxcb->rx_skb) + rtw_usb_rx_resubmit(rtwusb, rxcb, GFP_ATOMIC); } } @@ -653,15 +691,16 @@ static void rtw_usb_read_port_complete(struct urb *urb) urb->actual_length < 24) { rtw_err(rtwdev, "failed to get urb length:%d\n", urb->actual_length); - if (skb) - dev_kfree_skb_any(skb); + skb_queue_tail(&rtwusb->rx_free_queue, skb); } else { skb_put(skb, urb->actual_length); skb_queue_tail(&rtwusb->rx_queue, skb); queue_work(rtwusb->rxwq, &rtwusb->rx_work); } - rtw_usb_rx_resubmit(rtwusb, rxcb); + rtw_usb_rx_resubmit(rtwusb, rxcb, GFP_ATOMIC); } else { + skb_queue_tail(&rtwusb->rx_free_queue, skb); + switch (urb->status) { case -EINVAL: case -EPIPE: @@ -679,8 +718,6 @@ static void rtw_usb_read_port_complete(struct urb *urb) rtw_err(rtwdev, "status %d\n", urb->status); break; } - if (skb) - dev_kfree_skb_any(skb); } } @@ -868,16 +905,26 @@ static struct rtw_hci_ops rtw_usb_ops = { static int rtw_usb_init_rx(struct rtw_dev *rtwdev) { struct rtw_usb *rtwusb = rtw_get_usb_priv(rtwdev); + struct sk_buff *rx_skb; + int i; - rtwusb->rxwq = create_singlethread_workqueue("rtw88_usb: rx wq"); + rtwusb->rxwq = alloc_workqueue("rtw88_usb: rx wq", WQ_BH, 0); if (!rtwusb->rxwq) { rtw_err(rtwdev, "failed to create RX work queue\n"); return -ENOMEM; } skb_queue_head_init(&rtwusb->rx_queue); + skb_queue_head_init(&rtwusb->rx_free_queue); INIT_WORK(&rtwusb->rx_work, rtw_usb_rx_handler); + INIT_WORK(&rtwusb->rx_urb_work, rtw_usb_rx_resubmit_work); + + for (i = 0; i < RTW_USB_RX_SKB_NUM; i++) { + rx_skb = alloc_skb(RTW_USB_MAX_RECVBUF_SZ, GFP_KERNEL); + if (rx_skb) + skb_queue_tail(&rtwusb->rx_free_queue, rx_skb); + } return 0; } @@ -890,7 +937,7 @@ static void rtw_usb_setup_rx(struct rtw_dev *rtwdev) for (i = 0; i < RTW_USB_RXCB_NUM; i++) { struct rx_usb_ctrl_block *rxcb = &rtwusb->rx_cb[i]; - rtw_usb_rx_resubmit(rtwusb, rxcb); + rtw_usb_rx_resubmit(rtwusb, rxcb, GFP_KERNEL); } } @@ -902,6 +949,8 @@ static void rtw_usb_deinit_rx(struct rtw_dev *rtwdev) flush_workqueue(rtwusb->rxwq); destroy_workqueue(rtwusb->rxwq); + + skb_queue_purge(&rtwusb->rx_free_queue); } static int rtw_usb_init_tx(struct rtw_dev *rtwdev) diff --git a/drivers/net/wireless/realtek/rtw88/usb.h b/drivers/net/wireless/realtek/rtw88/usb.h index 86697a5c0103..9b695b688b24 100644 --- a/drivers/net/wireless/realtek/rtw88/usb.h +++ b/drivers/net/wireless/realtek/rtw88/usb.h @@ -38,6 +38,7 @@ #define RTW_USB_RXAGG_TIMEOUT 10 #define RTW_USB_RXCB_NUM 4 +#define RTW_USB_RX_SKB_NUM 8 #define RTW_USB_EP_MAX 4 @@ -81,7 +82,9 @@ struct rtw_usb { struct rx_usb_ctrl_block rx_cb[RTW_USB_RXCB_NUM]; struct sk_buff_head rx_queue; + struct sk_buff_head rx_free_queue; struct work_struct rx_work; + struct work_struct rx_urb_work; }; static inline struct rtw_usb_tx_data *rtw_usb_get_tx_data(struct sk_buff *skb) -- 2.47.1
